Out of the mainstream: Stromness, Orkney. The islands treasure their Norse heritage but want more respect from the mainland (credit: Geoff Wong)

The small propeller plane from Aberdeen out over the North Sea is packed. We are 20 passengers bound for Orkney, an archipelago of 70 inhabited and uninhabited land masses protruding from the grey-green swell. Our arrival coincides with the midsummer cultural festival of St Magnus which wakes through the mist like Brigadoon each year to welcome the outside world and then fall asleep again before the visitors can change it. Change, however, is afoot. The northern half of the greater island to which Orkney is adjacent, and therefore politically attached, has proposed to split itself off from the south, and every northerner who has reached the age of 16 has the opportunity to say, on the 18th day of this month, whether they wish to continue united or divided.

The plane is a leveller. There are well-known faces crammed into the tiny one-class fuselage. The composer Sir Peter Maxwell Davies is sitting with his eyes closed and his hands clasped between his legs. He prefers the ferry, but it is slower and there is a reception to attend. The actor John Sessions sits by a porthole and scans the playscript of his one-man show. The general manager of the BBC Singers is flying separately from his illustrious vocalists, who are already in rehearsal. The Minister of Culture for the Scottish National Party (SNP) leafs through papers in the seat nearest the emergency hatch. Some Italians applaud when the plane lands at Kirkwall, the capital, although His Excellency the ambassador in their midst remains aloof from demonstrative relief.

The reception is fuelled by Highland Park, a single malt whisky sponsoring the festival. A local hotelier sporting a green Yes badge beams bonhomie at the canapé table and is keen for Scotland's independence. "We can go it alone," he says, "We have the oil, we have the renewables, we have the golf." Later he will withdraw from the agreed interview after a haranguing from his wife and the resignation of his plumber for his indiscretion. A certain naivety attends the Yes campaign. A retired gentleman acknowledges the swelling enthusiasm for independence, but mourns what might be lost of history and ancient friendships. "It's creating division where none exists," he says. "The UK has an outline which gives it security. Why impose a new border? People always argue over borders."

Councillor Stephen Clackson is decisively indecisive. "On the one hand, I think Yes," he says, "because the Westminster coalition seems to be opening the country to exploitation by big business and demonising the poor, while with independence we'll be larger fish in a smaller pond with more influence on shaping a new nation." The fish analogy is apt as Clackson has spent the day travelling round his council ward by boat. "On the other hand, I think No," he continues, "because the SNP has a centralising agenda, removing control from the regions. There is now a single police force, Police Scotland, for the whole country. In power, the SNP has rewarded only the areas which support it. Orkney and Shetland vote Liberal Democrat and have been left out of the ferry investments the Hebrides get."

The festival director, the composer Alasdair Nicolson, welcomes everyone to the event, which costs a quarter of a million pounds but is worth much more to the local economy. Foreign guests are acknowledged. A Norwegian delegation is present to talk about the cathedral which their country gave Orkney in 1472 along with its independence. The Orkney flag is Norway's but for a band of yellow. There are Viking exhibits in the museum among the Neolithic bone implements and Bronze Age weaponry. Whole pre-Christian settlements have been dug up on the islands. They treasure their status as a World Heritage site and there is some resentment of the Scottish mainland's patronising attitude towards them.